refactor(renderer): decouple events from buffer manipulation

lua/opencode/config.lua

@@ -142,6 +142,11 @@ M.defaults = {
       rendering = {
         markdown_debounce_ms = 250,
         on_data_rendered = nil,
+        markdown_on_idle = false,
+        -- If set to a number, markdown rendering will be deferred while
+        -- `state.user_message_count[session_id]` is greater than this value.
+        -- If `nil`, the existing behavior is used (defer while > 0).
+        markdown_on_idle_threshold = nil,
         event_throttle_ms = 40,
         event_collapsing = true,
       },
@@ -255,6 +260,8 @@ M.defaults = {
     enabled = false,
     capture_streamed_events = false,
     show_ids = true,
+    highlight_changed_lines = false,
+    highlight_changed_lines_timeout_ms = 120,
     quick_chat = {
       keep_session = false,
       set_active_session = false,

lua/opencode/core.lua

@@ -545,6 +545,8 @@ M.initialize_current_model = Promise.async(function()
 end)
 
 M._on_user_message_count_change = Promise.async(function(_, new, old)
+  require('opencode.ui.renderer.flush').flush_pending_on_data_rendered()
+
   if config.hooks and config.hooks.on_done_thinking then
     local all_sessions = session.get_all_workspace_sessions():await()
     local done_sessions = vim.tbl_filter(function(s)

lua/opencode/id.lua

@@ -142,4 +142,3 @@ function M.get_prefixes()
 end
 
 return M
-

lua/opencode/throttling_emitter.lua

@@ -46,7 +46,9 @@ function ThrottlingEmitter:_drain()
   local items_to_process = self.queue
   self.queue = {}
 
-  self.process_fn(items_to_process)
+  if #items_to_process > 0 then
+    self.process_fn(items_to_process)
+  end
 
   -- double check that items weren't added while processing
   if #self.queue > 0 and not self.drain_scheduled then

lua/opencode/types.lua

@@ -172,6 +172,7 @@
 ---@class OpencodeUIOutputRenderingConfig
 ---@field markdown_debounce_ms number
 ---@field on_data_rendered (fun(buf: integer, win: integer)|boolean)|nil
+---@field markdown_on_idle boolean
 ---@field event_throttle_ms number
 ---@field event_collapsing boolean
 
@@ -207,6 +208,8 @@
 ---@field enabled boolean
 ---@field capture_streamed_events boolean
 ---@field show_ids boolean
+---@field highlight_changed_lines boolean
+---@field highlight_changed_lines_timeout_ms number
 ---@field quick_chat {keep_session: boolean, set_active_session: boolean}
 
 ---@class OpencodeHooks

lua/opencode/ui/base_picker.lua

@@ -85,6 +85,8 @@ local function telescope_ui(opts)
   local entry_display = require('telescope.pickers.entry_display')
 
   -- Create displayer dynamically based on number of parts
+  ---@param picker_item PickerItem
+  ---@return table
   local function create_displayer(picker_item)
     local items = {}
     for _ in ipairs(picker_item.parts) do
@@ -129,6 +131,7 @@ local function telescope_ui(opts)
     return entry
   end
 
+  ---@return unknown
   local function refresh_picker()
     return current_picker
       and current_picker:refresh(
@@ -232,6 +235,7 @@ end
 local function fzf_ui(opts)
   local fzf_lua = require('fzf-lua')
 
+  ---@return table
   local function create_fzf_config()
     local has_multi_action = util.some(opts.actions, function(action)
       return action.multi_selection
@@ -261,6 +265,7 @@ local function fzf_ui(opts)
     }
   end
 
+  ---@return fun(fzf_cb: fun(line?: string))
   local function create_finder()
     return function(fzf_cb)
       for idx, item in ipairs(opts.items) do
@@ -299,6 +304,7 @@ local function fzf_ui(opts)
     end
   end
 
+  ---Reopen fzf-lua to reflect updated picker items.
   local function refresh_fzf()
     vim.schedule(function()
       fzf_ui(opts)
@@ -644,6 +650,7 @@ function M.create_picker_item(parts)
     parts = parts,
   }
 
+  ---@return string
   function item:to_string()
     local texts = {}
     for _, part in ipairs(self.parts) do
@@ -652,6 +659,7 @@ function M.create_picker_item(parts)
     return table.concat(texts, ' ')
   end
 
+  ---@return table
   function item:to_formatted_text()
     local formatted = {}
     for _, part in ipairs(self.parts) do

lua/opencode/ui/dialog.lua

@@ -261,7 +261,11 @@ function Dialog:format_dialog(output, config)
   local end_line = output:get_line_count()
 
   if config.border_hl then
-    formatter.add_vertical_border(output, start_line + 1, end_line, config.border_hl, -2)
+    local border_end = end_line
+    if config.extend_border_to_trailing_blank then
+      border_end = border_end + 1
+    end
+    formatter.add_vertical_border(output, start_line + 1, border_end, config.border_hl, -2)
   end
 
   output:add_line('')
@@ -277,15 +281,22 @@ function Dialog:format_options(output, options)
       label = label .. ' - ' .. option.description
     end
 
-    local line_idx = output:get_line_count()
     local is_selected = self._selected_index == i
     local line_text = is_selected and string.format('    %d. %s ', i, label) or string.format('    %d. %s', i, label)
 
-    output:add_line(line_text)
+    -- Output uses 0-based indexing for extmarks. The correct target for
+    -- extmarks is the previous line count (0-based) because add_line will
+    -- append a new line and increase the 1-based line count. Capture the
+    -- current count first and then add the line so we can use that 0-based
+    -- index for extmarks.
+    -- add_line returns a 1-based line index; Output extmarks use 0-based
+    -- keys, so subtract 1 to get the correct extmark key.
+    local added_idx = output:add_line(line_text)
 
     if is_selected then
-      output:add_extmark(line_idx, { line_hl_group = 'OpencodeDialogOptionHover' } --[[@as OutputExtmark]])
-      output:add_extmark(line_idx, {
+      local extmark_idx = added_idx - 1
+      output:add_extmark(extmark_idx, { line_hl_group = 'OpencodeDialogOptionHover' } --[[@as OutputExtmark]])
+      output:add_extmark(extmark_idx, {
         start_col = 2,
         virt_text = { { '› ', 'OpencodeDialogOptionHover' } },
         virt_text_pos = 'overlay',
@@ -309,11 +320,16 @@ function Dialog:_setup_keymaps()
   if keymaps.up then
     for _, key in ipairs(keymaps.up) do
       if key and key ~= '' then
-        vim.keymap.set('n', key, function()
-          self:navigate(-1)
-        end, vim.tbl_extend('force', keymap_opts, {
-          desc = 'Dialog: navigate up',
-        }))
+        vim.keymap.set(
+          'n',
+          key,
+          function()
+            self:navigate(-1)
+          end,
+          vim.tbl_extend('force', keymap_opts, {
+            desc = 'Dialog: navigate up',
+          })
+        )
         table.insert(self._keymaps, key)
       end
     end
@@ -322,31 +338,46 @@ function Dialog:_setup_keymaps()
   if keymaps.down then
     for _, key in ipairs(keymaps.down) do
       if key and key ~= '' then
-        vim.keymap.set('n', key, function()
-          self:navigate(1)
-        end, vim.tbl_extend('force', keymap_opts, {
-          desc = 'Dialog: navigate down',
-        }))
+        vim.keymap.set(
+          'n',
+          key,
+          function()
+            self:navigate(1)
+          end,
+          vim.tbl_extend('force', keymap_opts, {
+            desc = 'Dialog: navigate down',
+          })
+        )
         table.insert(self._keymaps, key)
       end
     end
   end
 
   if keymaps.select and keymaps.select ~= '' then
-    vim.keymap.set('n', keymaps.select, function()
-      self:select()
-    end, vim.tbl_extend('force', keymap_opts, {
-      desc = 'Dialog: select option',
-    }))
+    vim.keymap.set(
+      'n',
+      keymaps.select,
+      function()
+        self:select()
+      end,
+      vim.tbl_extend('force', keymap_opts, {
+        desc = 'Dialog: select option',
+      })
+    )
     table.insert(self._keymaps, keymaps.select)
   end
 
   if keymaps.dismiss and keymaps.dismiss ~= '' then
-    vim.keymap.set('n', keymaps.dismiss, function()
-      self:dismiss()
-    end, vim.tbl_extend('force', keymap_opts, {
-      desc = 'Dialog: dismiss',
-    }))
+    vim.keymap.set(
+      'n',
+      keymaps.dismiss,
+      function()
+        self:dismiss()
+      end,
+      vim.tbl_extend('force', keymap_opts, {
+        desc = 'Dialog: dismiss',
+      })
+    )
     table.insert(self._keymaps, keymaps.dismiss)
   end
 
@@ -355,15 +386,20 @@ function Dialog:_setup_keymaps()
     local number_keymap_opts = vim.tbl_extend('force', keymap_opts, { nowait = true })
     for i = 1, math.min(option_count, 9) do
       local key = tostring(i)
-      vim.keymap.set('n', key, function()
-        if not self._active or not self._config.check_focused() then
-          return
-        end
-        self._selected_index = i
-        self._config.on_select(i)
-      end, vim.tbl_extend('force', number_keymap_opts, {
-        desc = 'Dialog: select option ' .. key,
-      }))
+      vim.keymap.set(
+        'n',
+        key,
+        function()
+          if not self._active or not self._config.check_focused() then
+            return
+          end
+          self._selected_index = i
+          self._config.on_select(i)
+        end,
+        vim.tbl_extend('force', number_keymap_opts, {
+          desc = 'Dialog: select option ' .. key,
+        })
+      )
       table.insert(self._keymaps, key)
     end
   end